This invention relates to print hammer assemblies and, more particularly, to print hammer assemblies used in impact serial printers of the type including a platen, a plurality of print elements and a marking medium interposed between the print elements and the platen. An example of an impact serial printer of this type is disclosed in U.S. Pat. No. 4,091,911, whereas an example of a print hammer assembly used in such a printer is disclosed in U.S. Pat. No. 4,037,532.
One problem with existing serial printers of the type disclosed in U.S. Pat. No. 4,091,911, which employ a rotatable print wheel mounted to a linearly movable carriage along with a print hammer assembly, the carriage being moved along a path parallel to the longitudinal axis of an adjacent cylindrical platen, has to do with misalignment of the platen. More specifically, the platen must be precisely aligned relative to the carriage such that the carriage path is parallel to the longitudinal axis of the platen. If this relationship is not true, the print elements of the wheel may impact the platen at other locations on the periphery, but not in alignment with the center line thereof during linear advancement of the carriage. For example, if the platen is inclined in a vertical plane from left to right, the top area of print elements impacting the left portion of the platen might be at least partially deleted, with the reverse being true with respect to impacts occurring at the right portion of the platen. This, of course, will lead to an uneven, and perhaps unintelligible print.
It would be desirable, therefore, to provide a print hammer assembly that would compensate for minor misalignments of the platen axis relative to the linear path of movement of the carriage to which the print hammer assembly and print elements are mounted.